Field of the Invention
The present invention relates to a control apparatus and a control method thereof.
Description of the Related Art
A liquid crystal display apparatus has a liquid crystal panel, a backlight disposed on the rear face side of the liquid crystal panel, and a control circuit for controlling the foregoing components.
In recent years, technology of dividing the backlight into a plurality of divided regions (light-emitting blocks) and controlling the brightness of each light-emitting block is being developed. This technology is capable of improving the contrast of the image displayed on the liquid crystal display apparatus, and reducing the power consumption. This kind of technology is referred to as local dimming.
With local dimming, image data is divied for each of the light-emitting blocks, and statistics (for instance, maximum gradation value) of the image data for each of the light-emitting blocks are obtained. In addition, the brightness of the light-emitting blocks is decided based on the acquired maximum gradation value (maximum brightness value) for each of the light-emitting blocks. Consequently, the brightness of the light-emitting blocks in a region of the image data with a high brightness value will be high, and the brightness of the light-emitting blocks in a region of the image data with a low brightness value will be low. Moreover, correction processing is performed to the image data based on the decided brightness for each of the light-emitting blocks so that, for instance, the brightness (display brightness) of the brightest part does not change for each of the light-emitting blocks. This kind of local dimming is disclosed, for example, in Japanese Patent Application Publication No. 2005-258403.
Conventional technology related to local dimming is also disclosed in, for instance, Japanese Patent Application Publication No. 2009-265671.
With the technology disclosed in Japanese Patent Application Publication No. 2009-265671, the representative gradation value for each of the light-emitting blocks is calculated from the image data. In addition, the fewer the light-emitting blocks having a representative gradation value that is not less than a reference value, the higher the brightness of the light-emitting blocks is set.